GSM SMSReceiver, sms.available() always return false


I am trying SMSReceiver example in GSM example using Arduino Uno and SIM900A board.

I am not able to receive any sms in my serial monitor.

I have connected pins 2,3 (Rx, Tx) of arduino Uno to SIM900A pins Tx and Rx.

the void setup() executesOK, while in void loop() the sketch is waiting to receive sms.

The sms.available() function is always false even though I am sending sms messages.

Please if somebody can point out where i am getting wrong

ReceiveSMS.ino (1.98 KB)